1. Field of the Invention
The present invention relates to a display device and more particularly to a liquid crystal display device excellent in reliability of a seal portion.
2. Description of the Related Art
The uses of liquid crystal display devices have been expanded into various fields because they can be made thin. In the liquid crystal display device, a color filter substrate having color filters or the like formed at places corresponding to pixel electrodes faces a TFT substrate having the pixel electrodes, thin film transistors (TFTs), or the like formed in a matrix, and liquid crystal is interposed between the TFT substrate and the color filter substrate. The transmittance of light through liquid crystal molecules is controlled in each pixel, so that an image is formed.
In the TFT substrate, data lines extending in the vertical direction and arranged in the lateral direction and scanning lines extending in the lateral direction and arranged in the vertical direction are present. A pixel is formed in a region surrounded by the data lines and the scanning lines. The pixel mainly includes the pixel electrode and the thin film transistor (TFT) as a switching element. A large number of pixels formed in a matrix as described above form a display region.
The TFT substrate and a counter substrate are bonded together via a sealing material formed at the peripheries of the substrates. In the display region in this case, a gap between the TFT substrate and the counter substrate is defined via column spacers formed on the counter substrate to form a liquid crystal layer to a predetermined thickness. In a seal portion, glass fibers are mixed into the sealing material, so that the thickness of the seal portion is defined by the diameter of the glass fiber.
However, when the way of determination for the gap between the TFT substrate and the counter substrate is different between the display region and the seal portion, the reliability of the seal portion is impaired, or display unevenness occurs due to the non-uniformity of the gap. JP-A-2001-174827 describes the configuration which makes the gap uniform between the TFT substrate and the counter substrate by using column spacers also in the seal portion.